<!DOCTYPE html>
<html>
    <head>
        <style>
            body {
                background-color: black;
            }
            div {
                width: 100%;
                height: 100%;
                border: 4px solid darkgreen;
                background-color: green;
                position: absolute;
                box-sizing: border-box;
                top: 0;
                left: 0;
            }
        </style>
    </head>
    <body>
        <div></div>
    </body>
</html>
